Apparently since BIOS version 1.29, the X220 cannot run high speed memory above 1333MHz. Meaning that JEDEC approved SODIMMs that can run at 1600 & 1866MHz are stuck running at 1333MHz with no option anywhere in the BIOS to force higher speed.

The last BIOS to support high speed memory was 1.28.

The question is, why did Lenovo see fit to remove this useful feature? Is this a bug or was this feature removal intentional? Are there plans to restore this feature in future BIOS revisions?

i never knew that a thinkpad bios had the capability to overclock the memory bus. i don't think i've ever seen such a setting. please expound, if you would please.

i was always under the impression that faster memory could be used as long as it was physically the same form factor and architecture. that the memory bus simply dictated the actual memory access speed vs its rated capability.

Your processor in X220 does not support any memory speed higher than 1333MHz - you can consult Intel specs to confirm it. The memory speed was limited to conform with Intel specs. And the reality is that the memory running at faster speed has almost zero impact on benchmarks, and even less impact on any real-world application.

If you require the memory running at faster speed, you can always stick with the older BIOS. There will never be any BIOS option to run memory at an unsupported speed.

I am aware of Intel's specs, as I am aware of Intel stating that said specs were 'locked' and released before memory running above 1333MHz had been JEDEC approved.

That is why, with proper high speed RAM (with SPD profiles etc), Sandy Bridge & Ivy Bridge automatically run the memory at the speeds it was designed for - unless this feature is intentionally blocked via the BIOS, which is what Lenovo has done with their latest updates.

Speaking of benchmarks, going from 1333MHz to 1866MHz yielded great improvement in graphics performance - the integrated GPU benefits greatly from the increase in RAM speed. Specifically, Windows 7 WEI score went from 5,8 to 6,3 and frame rates were up in almost all graphics intensive applications and games I tested.

Perhaps a BIOS setting could be added that permits higher memory speeds?

my x220, running bios v1.31, went to wei graphics scores of 6.3 simply by installing a matched 4gb pair of Hynix 1333mhz sticks. the scores went up an additional 0.1 after installing the most current video driver.

The WEI score on my X220 is also 6.3, with BIOS 1.31 and two 1333mHz 4 GB sticks (from Newegg, don't remember which brand). The score jumped from 5.7 to 6.3 when I updated the video driver sometime last year.